Andy, 8, has a dream - he wants to produce hisvery own dictionary. This is not an easy task forhim, as the number of words that he knows is,well, not quite enough. Instead of thinking up allthe words himself, he has a briliant idea. Fromhis bookshelf he
would pick one of his favouritestory books, from which he would copy out allthe distinct words. By arranging the words inalphabetical order, he is done! Of course, it isa really time-consuming job, and this is where acomputer program is helpful.You are asked
to write a program that listsall the different words in the input text. In thisproblem, a word is defined as a consecutive sequenceof alphabets, in upper and/or lower case.Words with only one letter are also to be considered. Furthermore, your program must
be CaSe InSeNsItIvE.For example, words like “Apple”, “apple” or “APPLE” must be considered the same.InputThe input file is a text with no more than 5000 lines. An input line has at most 200 characters. Inputis terminated by EOF.OutputYour output should give
a list of different words that appears in the input text, one in a line. Thewords should all be in lower case, sorted in alphabetical order. You can be sure that he number ofdistinct words in the text does not exceed 5000.Sample InputAdventures in DisneylandTwo
blondes were going to Disneyland when they came to a fork in theroad. The sign read: "Disneyland Left."So they went home.Sample Outputaadventuresblondescamedisneylandforkgoinghomeinleftreadroadsignso
题意：题目大意：给出一个文本，找出所有不同的单词。按字典序升序输出。Ps：单词不区分大小写。
题解;用到set<>容器（单词部分大小写，先将其转换为小写）；用到很多函数；
AC：
#include <iostream>
#include <string>
#include <algorithm>
#include <set>
#include <sstream>
using namespace std;
int main()
{
string str, buf;
set<string>a;
while(cin>>str)
{
for(int i=0;i<str.length();i++)
{
if(isalpha(str[i]))
str[i] = tolower(str[i]);
else
str[i] = ' ';
}
stringstream str2(str);
while(str2 >> buf)
{
a.insert(buf);
}
}
for(set<string>::iterator it= a.begin();it!=a.end();it++)
{
cout<<*it<<endl;
}
return 0;
}